Lighting systems in the prior art are typically formed by interconnecting, via a communications system, a plurality of lighting fixtures and providing for operator control of the plurality of lighting fixtures from a central controller. Such lighting systems may contain multiparameter light fixtures, which illustratively are light fixtures having two or more individually remotely adjustable parameters such as focus, color, image, position, or other light characteristics. Multiparameter lighting fixtures are widely used in the lighting industry because they facilitate significant reductions in overall lighting system size and permit dynamic changes to the final lighting effect. Applications and events in which multiparameter lighting fixtures are used to great advantage include showrooms, television lighting, stage lighting, architectural lighting, live concerts, and theme parks. Illustrative multi-parameter light devices are described in the product brochure entitled “The High End Systems Product Line 2001” and are available from High End Systems, Inc. of Austin, Tex.
A variety of different types of multiparameter light fixtures are available. One type of advanced multiparameter lighting fixture is an image projection lighting device (“IPLD”). Image projection lighting devices of the prior art typically use a light valve or light valves to project images onto a stage or other projection surface. A light valve, which is also known as an image gate, is a device for example such as a digital micro-mirror (“DMD”) or a liquid crystal display (“LCD”) that forms the image that is projected. Either a transmissive or a reflective type light valve may be used. U.S. Pat. No. 6,057,958, issued May 2, 2000 to Hunt, incorporated herein by reference, discloses a pixel based gobo record control format for storing gobo images in the memory of a light fixture. The gobo images can be recalled and modified from commands sent by a control console. A pixel based gobo image is a gobo (or a projection pattern) created by a light valve like a video projection of sorts. U.S. Pat. No. 5,829,868, issued Nov. 3, 1998 to Hutton, incorporated by reference herein, discloses storing video frames as cues locally in a lamp, and supplying them as directed to the image gate to produce animated and real-time imaging. A single frame can also be manipulated through processing to produce multiple variations. Alternatively, a video communication link can be employed to supply continuous video from a remote source.
IPLDs of the prior art use light from a projection lamp that is sent through a light valve and focused by an output lens to project images on a stage or a projection surface. The control of the various parameters of the IPLDs is affected by an operator using a central controller. In a given application, a plurality of IPLDs are used to illuminate the projection surface, with each IPLD having many parameters that may be adjusted by a central controller to create a scene.
IPLDs used in an entertainment lighting system can produce many colorful images upon the stage or projection surface. IPLDs may project images onto the projection surface such as still images, video images and graphic images. The term “content” is a general term that refers to various types of creative works, including image-type works and audio works. Content is typically comprised of still images, video images or loops and computer graphical images.
The Catalyst (trademarked) image projection lighting device manufactured by High End Systems of Austin Texas incorporates a video projector with a moveable mirror system that directs the images projected by the projector onto the stage or projection surface. A personal computer is used as a server that provides the images to the projector. A lighting controller sends command signals over a communication system to control the selection of images from the server to the projector as well as control the various functions of the video projector and the position of the image on the projection surface.
During a theatrical presentation the Image projection lighting devices are often operated in conjunction with theatrical fog generating devices. The theatrical fog or smoke generating devices are used to create an airborne haze that can be used as a projection surface creating three dimensional imagery. The fog generating devices create the airborne haze by propelling minute particles into the air which can remain suspended in the air for a considerable time. The minute particles are commonly created by the fog generating devices by atomization of oils or glycols. The glycol or mineral oil particles (referred to herein as fog particles) can each range in size from between twenty microns to below 0.1 micron.
When lighting devices such as image projection lighting devices contain complex optical and electronic components the fog particles may be drawn though the cooling system and may condense on the various optical components diffusing the projected image or shortening the life of the components. If a video projector is used for a component of the image projection lighting device, the video projector may often contain a filter system of its own. The filter system of the video projector offers very little protection for fog particles since most video projector filters rarely are effective on particles below ten microns such as those found in fog particles. Sanyo Electronics (trademarked) of Osaka, Japan has offered a filter cabinet called the Aircleanpro (trademarked) that uses an electrostatic air filtering system for improved operation of video projectors in cigarette smoke. Unfortunately a large percentage of fog particles are comprised of particles below ten microns since the airborne particles are in a continuous state of evaporation and electrostatic filters are not effective on these particles. There is a need to provide an image projection lighting device with a cooling filtration system that provides a high efficiency of filtration of fog particles below ten microns and that can provide a greater protection to the components of the image projection lighting device.